Electrical ring-furnace.



PATENTEB DEG. 5, 19057 E. MESBRn BLEGTRIAL RING FURNGE.

APPLICATION FILED APE. 26. 1904.

5 SHEETS-SHEET PATENTBD DEC. 5, 1905.

K. MEISBR. ELECTRICAL RING PURNCFt APPLICATION FILED APR. 26. 1004.

5 SHEETS-SHEET 2.

Z'nss 66 gg? M r u we f No. 806,690. PATENTED DEG. 5, 1905. K. MEISBR.

ELECTRICAL RING FURNAGE.

APPLICATION FILED APR.26,1904.

5 SHEETS-SHEET 3.

5 SHEETS-SHEET PTENTBD DEC. 5, 1905.

v L7-nem @75%967 APPLICATION I www5@ PATBNTBD DBG. 5, 1905.

APPLICATION FILED APR.26, 1904.

K MEISER ELECTRICAL RING FURNAGE.

UNITED STATES KARL MEISER, vOF NUREMBERG, GERMANY.

ELECTRICAL RING-FURNACE.

Specification of Letters Patent.

Fatented Dec. 5, 1905.

Application fried April ze, 1904. serai No. 205,006.

To all whom', t may concern.-

Beit known that I, KARL MEISER, engineer, residing in Nuremberg,Germany, have invented certain new and useful Improvements in ElectricalRing-Furnaces, of which the following is a clear description.

The chief advantages otiered by the ordinary electric furnaces are thatthe latter allow high temperatures to be obtained and that they are veryecient and can be easily regulated. .Notwithstanding thesedistinguishing features, cases occur sometimes in practice where the useof an ordinary electric furnace would not be advantageous, either froman industrial or from a technical point of view. In such cases the newelectric ring-furnace renders excellent services. It consists of aringconduit in which several electric ring-furnaces are arranged. Of thelatter but one isalways in operation, while the other furnaces are beingcooled down or subjected to a preliminary heating. This is eifected bycausing a current of air or of certain gases to circulate in thering-conduit and to transmit the heat, a similar eti'ect being thusproduced, like that obtained in the ordinary gas-heated ring-furnace,based upon the utilization of heated products of combustion. A

The new electric ring-furnace can be used in all those cases where goodresults are realized only when the material to be operated upon isheated very slowly-for example, in the manufacture of incandescent-lampfilaments. rIhe new electric ring-furnace will also iind application inthe case of all those substances which are not capable ot' conductingelectricity at an ordinary temperature, but become conductive in thepresence of higher temperatures. It', for example, raw pressedelectrodes for primary batteries were to be burned in an ordinaryelectric furnace, considerable difficulties would have to be overcome,the unburned electrode mass being nearly a non-conducting substance. Inthe present electric ring-furnace these difficulties are entirelyavoided by subjecting the electrodes to a preliminary heating eiiectbefore they are used for conducting the electric current.

The invention is illustrated in the accompanying drawings, in which-Figure l is a plan view. Figs. 2 and 3 are sections on the lines A B andC D of Fig. 1. Fig. 4 is a plan view of a modiiication. Figs. 5 and 6are sections on the lines E F and G I-I of Fig. 4L. Fig. 7 is a planview of a still further modification. Fig. 8 is a section on line I K ofFig. 7, and Figs. 9 and l0 show a further modification.

Referring first to Figs. 1 to 3, the electrodes p and n, which conveythe current, are arranged at the top and bottom of each chamber l 2 3,&c. The bottom electrodes remain always in position, while a topelectrode is introduced only into that compartment which is just atwork-vl. e., in the drawings into chamber 2. Chamber 2 is heated byelectricity, chambers 8 and 1 are cooled down, chambers 3 t 5 aresubjected to a preliminary heating, chamber 6 is recharged, and chamber7 is emptied. The heat from chambers 8 l 2 is conveyed into chambers 3 45 by the circulating air, which enters into chamber 8, flows throughchambers 1 2 3 L 5, and when slide t is open escapes from chamber 5 intoconduit The latter can be connected with the chimney by means of asimilar arrangement like that used in gas-heated ring-furnaces. However,the represented figures show a complete air circulation. It being a factthat while, on the one hand, a gas-heated ring-furnace requires acontinuous supply of gas and oxygen, for which products ot' combustionare let ofi3 therefrom in corresponding quantities, the electricring-furnace allows, on the other hand, a circuitous circulation of theair, which serves here only for conveying heat. In this manner any lossof heat in the chimney is avoided. A further advantage which thedescribed construction has over gas-heated ring-furnaces is that thereexists no longer any necessity to draw oftl the air from the lastchamber at the lowest possible temperature. The new furnace allows theair to be drawn oi from the last chamber at as high atemperature as50()D and even at higher temperatures, the entire heat which said aircontains being passed into the first chamber without waste. The heightof the temperature to be used for drawing ot'f depends solely upon whathighest temperature the new charge can stand without disastrous etfect.In this case the electric ring-furnace with circulatory action has theadvantage that only a small number of chambers is required, so that itcan be constructed at a small expense. The circulation is obtainedthrough a ventilator provided at e, which when slide a is open draws offthe air from chamber 5 into conduit and forces it from here into conduitf. When slide g is IOO open, the air'passes from conduitf into chamber 8and flows thereupon in the above-described manner through chambers 8 l 23 4 5. Chambers 5 and 8 are separated from the opened chambers 6 and 7by slides c and (il. As soon as the heating of the charge contained inchamber 2 is completed top electrode p is withdrawn and introduced intochamber 3. The further operations of shifting slides c and d, of closingchamber 6, and of opening chamber 8 cause chamber 6 to be inserted inthe circuit and chamber 8 to be put out of circuit, and so on.

In the electric ring-furnace represented in Figs. 4, 5, and 6 theelectrodes are arranged horizontally, chambers 6 and 7 are again open,and chambers 8 1 2 3 4L 5 are inserted in the circuit. When slide /t isopen, the air-current is drawn by the ventilator from cham ber 5 intocond uitz' and then pressed toward chamber 8, the slide v of which isalso opened. In Figs. l, 2, 3 a stationary ventilator is used. However,the one required for the construction shown in the followingfigure is amovable electroventilator capable of being shifted according as the fireprogresses. If, for example, chambers 7 8 are opened, theelectroventilator is inserted into conduit f through aperture Z, whichhad been previously closed by a cover, the air being thus drawn 0H fromcham ber 6 and passed toward chamber l.

In order to have the heat effectively transmitted by the air, the wallsinclosing the material to be operated upon must of course be as thin aspossible. In this connection the fact should also be mentioned that inthe electric ring-furnace the material to be treated becomes the hottestpart, while in a gasheated ring-furnace the products of combustionconstitute the hottest substance. The circulating air acts, therefore,in the furnacechamber as a cooling and at the same time also aspreserving mediuml upon the walls. This cooling action canbe regulatedby means of adjusting the number of revolutions made by the ventilator.

While I have used the term air in the foregoing description, any othersuitable gas can be used as a bearer of heat. rIhe use of air would ofcourse represent the simplest method. However, it is almost as easy towork with mixtures of nitrogen and carbonicoxid gas or carbonio acid.rI`hese gases may be readily produced my means of throwing some livecoal into the new chamber to be inserted. If other gases have to be usedfor the work, the chamber in question, which is closed at first by acover and slide, must of course be filled with gas in order to expel allair before said chamber is inserted in the circuit. 'Ihe joints of thecover and the slide are made close, as usually, by means of clay or thelike.

In many cases it is possiblel by the use of special gases to cause thematerial to be treated to be burned in the electric 'ring-furnacedirectly without being surrounded by a fireproof casing. An examplewhich proves this assertion are the electrodes, which when nitrogen andcarbonic-oxid are used for obtaining the circulating gas can be burnedand treated with graphite without any protecting-case.

Figs. 7 and 8 showacombination of the new electric ring-furnace with thewell-known gasheating ring-furnace. Such combination has the economicaladvantage that electricity, which is usually expensive, has only to beused for bringing about such increased temperature that can no longer beobtained with the aid of gas. In the figures, fm, is the gas-conduit,whence the gas enters into the furnacechamber-/. e., into chamber .Lofthe figure; when the slides are accordingly opened. The gas is burned insaid chamber with the heated air in the same manner as it is done inordinary gas-heated ring-furnaces. On reaching the highest gastemperature the gas is cut off and the electric current inserted. Whenheated by electricity, the furnace can work with circuitous air or gascirculation exactly as it has been described heretofore, so that no heatat all is lost hereby in the chimney. To this purpose chimney-slide r1.is closed and ventilator 0 is set to work. Willen the slides areproperly opened, said ventilator draws ofi' the gas from chamber 8 andpasses it through conduit 71 into chamber 11. In order that this gasfiowing from chamber 8 to chamber 1l may pass over the shortest course,slides c in the wind-conduit m are closed. In the described combinedfurnace all thc advantages of the electric ring-furnaces are alsorealized, except that no indifferent gases are used, the latter being'provided by the gases of combustion. Attention may finally be called tothe arrangement of the electrodes shown in Figs. 7 and 8, which diifersfrom that represented in the other figures. In this case twofurnace-chambers are provided for each compartment. They are connectedin the bottom by means of a conductor t, both electrodes being thusplaced above the furnace.

A modified execution is also represented in Figs. 9 and l0, allowing thefurnace-chambers themselves to be combined to a ring-conduit. In thelatter the material to be treated is arranged alternately withelectrodes p. Two particular electrodes are connected with the circuit,so that the current circulates between them. The air circulation is asbefore described.

Having thus described my invention, what I claim isl. An electricring-furnace comprising' a ring-conduit, a series of chambers therein,means for electrically heating said chambers, a second conduit,connections between the ring-conduit and said second conduit, slidescontrolling said connections, a passage leading from the second conduit, connections from IOO IOS

IIO

10 second conduit, connections from said passage to the chambers andslides controlling said connections and a Ventilator for producing acirculation of air and gas.

ln witness whereof I have hereunto set my hand in presence of twowitnesses.

KARL MEISER.

Witnesses:

ANDREAS STIcI-I, HENRY B. MEIsER.

